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the result was a good growth period in the summer until August and September. The weather <br />changed again to dry and very hot for the late summer period. Record and near record heat and <br />dryness occurred throughout much of eastern Colorado. This was in spite of a neutral ENSO climate <br />pattern. <br />This dry and hot pattern finally changed in November and December with good snowfall <br />although the average temperatures generally remained above normal. By the end of the year, a <br />second weak to moderate La Nina pattern redeveloped in the equatorial Pacific, but its effects were <br />not seen in the weather patterns until the very end of December. Long range forecasts seem to be <br />trending toward a drier and warmer winter for early 2012 with a return to a general northwest flow as <br />occurred in late 2010 and early 2011. The La Nina may decline by summer 2012. <br />Weed Control Issues: Leafy spurge remains the dominant noxious weed throughout the site, but <br />the strong grass growth in recent years certainly has restricted its expansion and dominance. It can <br />still be found in essentially every habitat on the site except reclaimed mined land, upland sand near <br />mining sites, and in the wetlands along the stream. Its abundance though appears to continue to show <br />a slow decline in most habitats. Localized control measures has also helped limit its expansion. <br />As was noted in previous reports, with the increased growth of grasses due to the removal of <br />grazing the spurge continued to decline in density throughout the area. It is still a fairly robust and <br />tenacious growth, but with better management the spurge is not as strong as it was previously and the <br />dominance gain among the grasses seems to continue the decline in spurge. Continued control <br />measures are having the desired effect of further reducing the spurge, but there is still a great deal to <br />be done to bring the spurge population down to a reasonable level. Although no quantitative data <br />were collected, visual inspection showed that in 2011 spurge continued its decline as natives gained <br />more ground in the middle part of the season. The prodigious moisture of mid spring normally would <br />favor spurge expansion, but if that occurred it was so slight it was not noticeable. Grass density and <br />condition is so good now that spurge is confined and expansion difficult due to competition. Once <br />again it is found that excellent management and maintenance of dense growth of native species can <br />greatly limit weed expansion, even with species as competitive as leafy spurge. Drowning the land in <br />herbicide really is not necessary if the land is properly managed and protected from, most especially, <br />overgrazing. Herbicide use can then be limited to only those areas where disturbance maintains the <br />weed growth or there was a near total dominance by spurge to begin with. <br />The remaining small Tamarix population treated in previous years has apparently been <br />eliminated. Only one additional plant was found in 2011. Is the invasion over? Perhaps, but <br />inspection and monitoring of the area needs to be continued for a few more years to be sure no more <br />appear from long seed dormancy or changing growth conditions. In favor of at least a very limited <br />return of this demonic species is the development of the vegetation in the area of the infestation. <br />When the infestation was first discovered, native growth was extremely limited and in poor <br />2011 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 3 <br />